The Expression And The Significance Of Livin And Caspase-3 In The Colorectal Cancer And Adenoma

Objective: Colorectal cancer is one of the common gastrointestinal neoplasms, and its incidence rate is rising. It is the third leading death rate in all cancer in the west world. Although the different available therapies, which including surgical operation, radiotherapy, and chemical therapy, have currently been used in the treatment of colorectal cancer, and all of these have markedly improved the prognosis of colorectal cancer. However results are not satisfied. Five-year survival rate for colorectal cancer, is about 50%-60%, has not improved substantially over the past 25 years. As for the patients visiting, majority have already been advanced because there are not overt symptoms in the early period of colorectal cancer. So the correct early diagnosis is important to the patients.Livin is a novel member of the inhibitors of apoptosis protein (IAP) gene family. Livin is selectively expressed in the most common human neoplasms and appears to be involved in tumor cell resistance to chemotherapeutic agents. High Livin expression in neoplasms correlates with the development and progression and survial time. Livin may be a possible new target for cancer diagnosis and therapy.To investigate the contribution and mechanism of Livin during the development and progression of colorectal cancer, we detected the expression of Livin and caspase-3 in normal colorectal mucosa, primary colorectal carcinoma and adenoma by using semi-quantitative RT-PCR and immunohistochemical method, then analyzed the relationship between Livin and the clinicopathoplogic features of colorectal cancer and the relationship between Livin and caspase-3 in the colorectal cancer.Methods: 1 Semi-quantitative RT-PCR: The present study was proformed to detect the expression of Livin mRNA, caspase-3 mRNA andβ-actin mRNA by using RT-PCR and measured the expression level of Livin-αmRNA, Livin-βmRNA, caspase-3 mRNA compared with the level ofβ-actin mRNA, then analyzed the results.2 Immunohistochemistry was performed by using the SP method. We used anti-Livin (1:100 dilution) and anti-caspase-3 (1:200 dilution) to detect the expression of Livin and caspase-3 protein in samples, then analyzed the results with the clincopathologic features .Results: 1 In the present study, we examined the expression of Livin and caspase-3 mRNA in 81 cases of colorectal cancer, 25 cases of adenoma and 40 cases of normal colorectal mucosa by Semi-quantitative RT-PCR. In all samples Livin-α, Livin-β, caspase-3 mRNA were detected.The expression relative quantity of Livin-αmRNA were 0.34±0.17 in colorectal carcinoma, 0.33±0.13 in adenoma and 0.12±0.11 in normal colorectal mucosa. The Livin-αmRNA expression relative quantity was significantly higher in colorectal cancer and adenoma than in normal colorectal mucosa (P<0.05). The difference of Livin-αmRNA expression quantity between colorectal cancer and adenoma was not statistically significant (P=0.978>0.05).The expression relative quantity of Livin-βmRNA were 0.32±0.04 in colorectal carcinoma, 0.47±0.10 in adenoma and 0.65±0.13 in normal colorectal mucosa. The Livin-βmRNA expression relative quantity was significantly lower in colorectal cancer than in normal colorectal mucosa (P=0.028<0.05). The difference of Livin-βmRNA expression quantity was not statistically significant between colorectal cancer and adenoma (P=0.261>0.05), between adenoma and normal colorectal mucosa (P=0.222>0.05).The value of Livinα/βwere 1.21±0.20 in colorectal carcinoma, 0.77±0.12 in adenoma and 0.28±0.10 in normal colorectal mucosa. The value of Livinα/βdecreased from colorectal cancer to normal colorectal mucosa. There were statistical significance between every two groups (P<0.05).The expression relative quantity of caspase-3 mRNA were 0.38±0.20 in colorectal carcinoma, 0.52±0.06 in adenoma and 0.81±0.16 in normal colorectal mucosa. The caspase-3 mRNA expression relative quantity was significantly higher in normal colorectal mucosa than in colorectal cancer (P=0.000 <0.05).In colorectal cancer, The Pearson correlation analysis showed that the relative quantity of Livin-αmRNA was weak negative related to that of Caspase-3 mRNA (r=-0.128, P=0.614 >0.05), Livin-βmRNA was weak positive related to that of Caspase-3 mRNA (r=0.225, P=0.369>0.05), the value of Livinα/βwas weak negative related to that of Caspase-3 mRNA (r=-0.218, P=0.386>0.05).2 Immunohistochemistry assay result showed that the positive expression rates of Livin protein in colorectal cancer, concurrent adenoma with cancer, adenoma and normal colorectal mucosa were 67.90% (55/81), 61.54% (8/13), 75.00% (9/12) and 0.00% (0/40); the positive expression rates of Caspase-3 protein were 40.74% (33/81), 69.23% (9/13), 58.33% (7/12) and 87.50% (35/40). In well, moderately and poorly differentiated adenocarcinoma the positive expression rates of Livin were 69.23% (18/26), 72.22% (26/36) and 57.89% (11/19); the positive expression rates of Caspase-3 were 53.85% (14/26), 41.67% (15/36) and 21.05% (4/19). By statistic analysis, Livin protein expression rate was higher in primary colorectal cancer than in normal colorectal mucosa (χ2 =42.52 P<0.05), Livin protein expression rates were not statistically significant between colorectal cancer and adenoma (χ2=0 P>0.05), between concurrent adenoma with cancer and adenoma (χ2=0.085 P>0.05).The difference in rates between adenoma and normal colorectal mucosa was statistically significant (χ2=29.52 P<0.05). The expression rates of Caspase-3 protein decreased from normal colorectal mucosa to colorectal cancer. There were statistical significance between every two groups (P<0.05). Then the relationships among Livin, caspase-3 and the clinicopathoplogic features of colorectal cancer were analyzed. Both Livin and caspase-3 protein expression in primary colorectal cancer had no significant correlation with patient's sex, age, cell differentiation level, Dukes stages, chorion invaded and lymph nodes metastasis or not (P>0.05).The Spearman rank correlation analysis method was used to analyze the correlation of Livin and Caspase-3. It showed that the expression of Livin was negative related to that of Caspase-3 in colorectal cancer (r=-0.294, P=0.008<0.01). Conclusions: 1 The positive expression rates of Livin protein were higher in primary colorectal cancer and in adenoma than in normal colorectal mucosa. It suggested that Livin protein expression was related with the development and progression of colorectal cancer and adenoma.2 The expression rates of Caspase-3 protein decreased from normal colorectal mucosa, adenoma to colorectal cancer. There were statistical significance between every two groups. It suggested that the decrease of Caspase-3 protein expression correlated with the development and progression of colorectal cancer and adenoma.3 Both Livin and caspase-3 protein expression in primary colorectal cancer had no significant correlation with patient's sex, age, cell differentiation level, Dukes stages, chorion invaded and lymph nodes metastasis or not. 4 In colorectal cancer, Livin may prevent cell apoptosis though the inhibition to activation of Caspase-3. And Livin was negative related to that of Caspase-3 .5 The Livin-αmRNA expression quantity was significantly higher in colorectal cancer and adenoma than in normal colorectal mucosa. It indicated that the increase of Livin-αmight be related with the genesis and progression of colorectal cancer, might be one of the earlier molecular events.6 The expression quantity of Livin-βmRNA was significantly lower in colorectal cancer than in normal colorectal mucosa, indicating that the decrease of Livin-βmight be related with the genesis and progression of colorectal cancer.7 The value of Livinα/βincreased from normal colorectal mucosa, adenoma to colorectal cancer. It indicated that it was both the increase of Livin-αand the decrease of Livin-βthat contributed to the genesis of colorectal cancer.